The present invention relates to a surveying technique using a photographed image taken by an aerial vehicle.
Aerial photogrammetry is widely used. This technique may use a large number of measurement targets that are placed on a ground to be surveyed in a condition in which the locations of the measurement targets are determined beforehand. These targets are photographed from the air to obtain aerial photographs, and various kinds of survey data are obtained from the aerial photographs. For example, one such technique is disclosed in Japanese Unexamined Patent Application Laid-Open No. 2013-061204.